On Wed, Nov 23, 2022 at 12:25:32PM -0400, Jason Gunthorpe wrote: > On Wed, Nov 23, 2022 at 04:37:59PM +0100, Greg Kroah-Hartman wrote: > > static inline struct device *__kobj_to_dev(struct kobject *kobj) > > { > > return container_of(kobj, struct device, kobj); > > } > > > > static inline const struct device *__kobj_to_dev_const(const struct kobject *kobj) > > { > > return container_of(kobj, const struct device, kobj); > > } > > > > /* > > * container_of() will happily take a const * and spit back a non-const * as it > > * is just doing pointer math. But we want to be a bit more careful in the > > * driver code, so manually force any const * of a kobject to also be a const * > > * to a device. > > */ > > #define kobj_to_dev(kobj) \ > > _Generic((kobj), \ > > const struct kobject *: __kobj_to_dev_const, \ > > struct kobject *: __kobj_to_dev)(kobj) > > > > > > Want me to do the same thing here as well? > > It would be nice to have a shared macro code gen all of the above > instead of copy and pasting it. Then maybe other cases beyond struct > device could adopt const too.. I think I tried to create such a beast, but failed, so ended up open-coding it in a few places in the USB headers already. I can try it again, but the redirection gets tricky (defines creating defines...) thanks, greg k-h